On a security door, the only enforceable thermal threshold is the one in article 9 of the French order of 3 May 2007: Ud ≤ 2 W/(m².K) for an external entrance door of a detached house, installed or replaced. Article 8 of the same order takes out of scope elements with a particular characteristic, and names burglar resistance among them, just as it excludes every entrance door other than a detached house one. On a flat entrance door, in other words, no Ud threshold applies at all, and the governing text becomes article 8 of the order of 31 January 1986, expressed as a fire integrity rating. The trade-off to document is therefore not thermal against security, it is regulatory against commercial.
What the regulations actually require on an opening
The thresholds of the order of 3 May 2007, and its exclusions
The French order of 3 May 2007 applies to glazed elements installed or replaced in an existing building. Article 9 sets the thresholds, article 8 draws the scope, and it is article 8 that decides the fate of a security door. The table below sets out both, and reads as the first line of a calculation note rather than as a sales argument.
| Element replaced | Performance requirement | Basis |
|---|---|---|
| Window over 0.5 m², French door, secondary window, curtain wall | Uw ≤ 1.9 W/(m².K) | article 9 |
| External entrance door of a detached house | Ud ≤ 2 W/(m².K) | article 9 |
| Rooflight | Ucw ≤ 2.5 W/(m².K) | article 9 |
| Heated conservatory | Uconservatory ≤ 2.5 W/(m².K) | article 9 |
| Entrance door other than a detached house one | out of scope | article 8 |
| Element with a particular characteristic, burglar resistance included | out of scope | article 8 |
Two consequences for your quote. On a detached house, a standard security door has to be able to state a Ud, and a Ud of 2 W/(m².K) at most if you do not rely on the burglar resistance exclusion. In a block, the flat entrance door falls under no threshold, which moves the whole issue onto the fire rating. How a declared coefficient is read, what it covers and where it traps you is set out in the surface heat transfer coefficient Uw.
The fire rating that governs in collective housing
Article 8 of the French order of 31 January 1986 requires flat entrance door sets serving dwellings in second-family collective buildings and in third-family buildings to be fire resisting for a quarter of an hour in integrity, and those of the fourth family for half an hour. The rating covers the complete door set, frame, leaf and hardware, tested in configuration. It is evidenced by a test report that must bear the same commercial reference as the product delivered, failing which it proves nothing.
The burglar resistance levels, and what they cover
A2P residential door set certification is issued by CNPP under its T64-1 technical rules, after testing the complete set. The certified characteristic is the ability to resist, for a given time, reasoned attacks carried out with defined tools, and the three levels correspond to increasing durations. The exact duration and the associated tool scenario sit in the technical rules, the only document that binds: do not repeat durations quoted in reseller literature without checking them against the referential.
| A2P door set level | What is certified | What is not |
|---|---|---|
| BP1 | Complete set tested in configuration, frame, leaf and hardware | A leaf alone, an added armour plate |
| BP2 | Complete set tested in configuration, frame, leaf and hardware | A lock fitted after the test |
| BP3 | Complete set tested in configuration, frame, leaf and hardware | Installation departing from the certificate's instructions |
Standard EN 1627 separately ranks closures in six increasing classes, RC1 to RC6, on a comparable principle. Equivalences between A2P levels and RC classes circulate widely and appear in no text: if a client asks for one, send them to the product certificate. The point that matters on site remains the scope: certification covers a tested assembly, never a leaf on its own. An armour plate added to an existing door falls under none of these levels, and it makes the original fire test report unusable as evidence.
What you record before ordering the set
The survey that secures the order
A security door is ordered on finished reveal dimensions and on a verified substrate, not on the dimensions of the existing leaf. Four lines are enough, provided they are measured.
- Reveal dimensions at three points, height and width, plus squareness and flatness taken with a straightedge.
- Nature and thickness of the fixing substrate, with a probe if there is any doubt about a stud wall or a thick render.
- Building family and required fire rating, taken from the building's own rules or from the managing agent.
- Finished floor level on both sides, which decides the threshold and the clearance under the bottom seal.
The frame, which carries both the security and the thermal performance
On a door set, the frame decides everything: it takes the forced-entry loads, it conducts heat around the perimeter, and it receives the perimeter seal. A steel frame with no thermal break builds a cold bridge into the opening itself, and no amount of leaf insulation makes that back. The principle, its orders of magnitude and how to check it on documentation are covered in thermally broken aluminium joinery.
The installation configuration, which changes the installed Ud
The Ud printed on the product fiche is measured on the opening alone in a laboratory. What gets paid for in use is the performance of the complete opening, perimeter seal and reveal included. Full removal with the reveal treated and installation onto a retained frame do not give the same result, and the gap gets documented rather than guessed: the two configurations are compared in full removal versus installation onto the existing frame.
The points that carry your liability
The perimeter seal, which decides the airtightness
The joint between frame and masonry is not a finish, it is the work. It is executed as a continuous run, with a barrier on the inside and a driving-rain protection on the outside, and it is inspected before the linings go on, not after. On a security door the constraint is twofold: the frame is massive and barely deforms, which forgives an out-of-square opening badly, and the weight of the leaf calls for a fixing that foam does not replace. The treatment of the perimeter follows the same logic as the insulation of the window reveal in external wall insulation.
The threshold, the low point of a heavy assembly
The threshold concentrates three requirements that contradict each other: airtightness, water resistance and level access. A security door adds the question of load transfer onto an applied threshold. Record the finished level on both sides before ordering, choose a thermally broken threshold when the frame has one, and check the compression of the bottom seal across the full width at handover, seal by seal. A visible gap at the bottom cancels the thermal benefit of the whole set.
The documents to file with the job
Three documents, and they must carry the exact commercial reference of the product delivered: the product fiche with the declared Ud, the fire test report where the set is a flat entrance door carrying a rating, and the A2P certificate with its level. Add the fixing photographs taken before the linings and the handover record with the clearance check. In the event of a claim or an insurance dispute, those are the papers that separate a defensible installation from one to be redone, and they accumulate through the pricing stage in a quote that carries the joinery and the associated works line by line.
What you tell the client, and what you do not
No national grant on this item
The BAR-EN-104 measure covers the window, the roof window and the full French door with insulating glazing, subject to Uw ≤ 1.3 W/(m².K) with Sw ≥ 0.3, or Uw ≤ 1.7 with Sw ≥ 0.36. The entrance door enters no standardised residential measure. Announcing a grant on this item exposes you to a rejected file and to a claim at final account. Say it at the first appointment, and price the door as a security item rather than as an energy retrofit measure.
The real thermal gain, at its true scale
An entrance door covers something like 2 m² in an envelope that often runs past two hundred. Even moving from a very poor opening to a high-performance one, the item weighs little in the overall balance, and promising it as a saving lever weakens everything else on the quote. What sells honestly is the disappearance of the draught at the threshold, the comfort of a leaf that stops being cold to the touch, and the acoustic reduction. Those three effects are observed, not calculated in kilowatt hours.
Where the door belongs in a work plan
A security door belongs in the same work plan as the rest of the envelope, with dimensions taken from the same survey, so that the reveal does not have to be reworked six months after external wall insulation. Framed at that level it is priced alongside the joinery and the induced works, it is installed in the right order, and it stops being an option added at the end. That is the only way to keep security and thermal performance from contradicting each other on site rather than on paper.
